This application is based on Japanese Patent Application 2000-243930, filed on Aug. 11, 2000, the entire contents of which are incorporated herein by reference.
a) Field of the Invention
The present invention relates to a semiconductor device manufacture method and a semiconductor device, and more particularly to a method of manufacturing a semiconductor device having a capacitor with a capacitor dielectric layer made of dielectric oxide and to such a semiconductor device.
In this specification, a high dielectric substance means a dielectric substance having a relative dielectric constant of 20 or larger.
b) Description of the Related Art
Semiconductor memories such as a dynamic random access memory (DRAM) and a ferroelectric random access memory (FeRAM) use a capacitor as a memory element. The performance of a memory element can be improved by improving the capacitor performance. It becomes easy to form a DRAM of a micro fine pattern by using a high dielectric capacitor having a capacitor dielectric layer of a high dielectric constant. If a ferroelectric capacitor is used, a non-volatile memory can be formed.
If a high dielectric oxide layer or a ferroelectric oxide layer is used as a capacitor dielectric layer, the lower and upper electrodes of the capacitor are desired to be made of conductive metal oxide, metal which cannot be oxidized, or metal which maintains conductivity even if it is oxidized. By using the electrodes made of such materials, it becomes easy to form a capacitor dielectric layer having good dielectric characteristics.
As the metal which is not oxidized or maintains conductivity even if it is oxidized, rare metal which contains noble metal such as Ru and Pt is known. As the metal oxide having a conductivity, RuOx, SrRuO3 and the like are known. These metal and metal oxide have only a small adhesion force to insulating material such as silicon oxide. Semiconductor devices are required to use interlayer insulating films made of SiO2 or the like. If the adhesion force to an interlayer insulating film is weak, it is difficult to use such materials in a semiconductor device.
It is desired to use electrodes made of rare metal for a capacitor having a good performance. However, the electrode made of rare metal has only a small adhesion force to an insulating film. It has therefore been desired to increase the adhesion force of an electrode made of rare metal to an insulating film.
It is an object of the present invention to provide a semiconductor device manufacture method capable of increasing the adhesion force between a rare metal layer and an insulating film.
It is another object of the invention to provide a semiconductor device excellent in the adhesion force between a rare metal layer and an insulating film.
According to one aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: (a) depositing a capacitor dielectric layer on a semiconductor substrate having a lower electrode made of rare metal formed on a surface of the semiconductor substrate, the capacitor dielectric layer being made of high dielectric oxide having a high dielectric constant or ferroelectric oxide; (b) forming a laminated layer on the capacitor dielectric layer, the laminated layer including an upper electrode layer made of rare metal and an adhesive layer; (c) patterning the laminated layer; (d) chemically processing the patterned, laminated layer to change a surface layer of the laminated layer; and (e) forming an interlayer insulating film over the semiconductor substrate, covering the chemically processed, laminated layer.
According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: (a) depositing a capacitor dielectric layer on a semiconductor substrate having a lower electrode made of rare metal formed on a surface of the semiconductor substrate, the capacitor dielectric layer being a high dielectric layer having a high dielectric constant or a ferroelectric layer; (b) forming a laminated layer on the capacitor dielectric layer, the laminated layer including an upper electrode layer made of rare metal and an adhesive layer; (c) patterning the laminated layer; (d) thermochemically processing the patterned, laminated layer to change a surface layer of the laminated layer; and (e) forming an interlayer insulating film over the semiconductor substrate, covering the thermochemically processed, laminated layer.
According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: (a) depositing a capacitor dielectric film made of dielectric oxide on a semiconductor substrate having a lower electrode made of Ru; (b) forming a laminated layer on the capacitor dielectric layer, the laminated layer having an upper electrode layer made of Ru, a TiN adhesive layer and an SiO2 mask layer; (c) pattering the laminated layer; (d) chemically processing the patterned, laminated layer with HF containing solution to partially remove the SiO2 mask layer; and (e) forming an interlayer insulating layer over the semiconductor substrate, covering the chemically processed SiO2 mask layer.
According to another aspect of the invention, there is provided a semiconductor device comprising: a semiconductor substrate formed with an active element; a first interlayer insulating film formed on the semiconductor substrate; a lower electrode layer disposed on the first interlayer insulating film, made of rare metal, and electrically connected to the active element; a capacitor dielectric layer disposed on the lower electrode layer and made of high dielectric material having a high dielectric constant or ferroelectric material; an upper electrode layer disposed on the capacitor dielectric layer and made of rate metal; an adhesive layer disposed on the upper electrode layer and having a same plan shape as that of the upper electrode layer; an insulating mask layer disposed on the adhesive layer and having a side wall positioned retracted from a side wall of the adhesive layer; and an interlayer insulating film formed over the semiconductor substrate, covering the insulating mask layer, upper electrode layer, capacitor dielectric layer and lower electrode layer.
With the above-described manufacture steps and device structure, the adhesion force between a rare metal electrode and an insulating film such as an interlayer insulating film can be increased.
A semiconductor device with a high dielectric capacitor or ferroelectric capacitor having a high reliability interlayer insulating film can be provided.